Conventional data storage systems include one or more storage devices connected to a controller or manager. As used herein, the term “data storage device” refers to any device or apparatus utilizable for the storage of data, e.g., disk drive. For explanatory purposes only and not as an intent to limit the scope of the invention, the term “disk drive” as used in this document is synonymous with the term “data storage device.”
To protect against the loss of data in the event of a disk drive failure, redundant copies of the data may be kept on multiple disks such that if a disk fails, its contents can be reconstructed from the redundant data on the other disks. Traditionally, a service person will physically replace the failed disk with a new one. However, this approach can cause undue delay in the restoration of data redundancy and may lead to the loss of the data entirely. Another common approach is to have a hot standby disk that is not in use, but can be used to automatically replace a disk that fails. The main drawback of having a hot standby disk is that additional idle hardware must be purchased, which is both expensive and inefficient.
A method and system for restoring data redundancy without the use of a hot standby disk is disclosed. Instead of having a hot standby disk, reserve storage space is maintained in the disk drives. In one embodiment, the reserve storage space comprises unallocated storage space on the disk drives. Once a disk drive failure is detected, data redundancy is restored on the reserve storage space.
Further details of aspects, objects, and advantages of the invention are described below in the detailed description, drawings, and claims. Both the foregoing general description and the following detailed description are exemplary and explanatory, and are not intended to be limiting as to the scope of the invention.